In vivo Imaging and Pharmacokinetics of Percutaneously Injected Ultrasound and X-ray Imageable Thermosensitive Hydrogel loaded with Doxorubicin versus Free Drug in Swine.

Intratumoral injections often lack visibility, leading to unpredictable outcomes such as incomplete tumor coverage, off-target drug delivery and systemic toxicities. This study investigated an ultrasound (US) and x-ray imageable thermosensitive hydrogel based on poloxamer 407 (POL) percutaneously delivered in a healthy swine model. The primary objective was to assess the 2D and 3D distribution of the hydrogel within tissue across three different needle devices and injection sites: liver, kidney, and intercostal muscle region. Secondly, pharmacokinetics of POL loaded with doxorubicin (POLDOX) were evaluated and compared to free doxorubicin injection (DOXSoln) with a Single End Hole Needle. Utilizing 2D and 3D morphometrics from US and x-ray imaging techniques such as Computed Tomography (CT) and Cone Beam CT (CBCT), we monitored the localization and leakage of POLDOX over time. Relative iodine concentrations measured with CBCT following incorporation of an iodinated contrast agent in POL indicated potential drug diffusion and advection transport. Furthermore, US imaging revealed temporal changes, suggesting variations in acoustic intensity, heterogeneity, and echotextures. Notably, 3D reconstruction of the distribution of POL and POLDOX from 2D ultrasound frames was achieved and morphometric data obtained. Pharmacokinetic analysis revealed lower systemic exposure of the drug in various organs with POLDOX formulation compared to DOXSoln formulation. This was demonstrated by a lower area under the curve (852.1 ± 409.1 ng/mL·h vs 2283.4 ± 377.2 ng/mL·h) in the plasma profile, suggesting a potential reduction in systemic toxicity. Overall, the use of POL formulation offers a promising strategy for precise and localized drug delivery, that may minimize adverse effects. Dual modality POL imaging enabled analysis of patterns of gel distribution and morphology, alongside of pharmacokinetics of local delivery. Incorporating hydrogels into drug delivery systems holds significant promise for improving the predictability of the delivered drug and enhancing spatial conformability. These advancements can potentially enhance the safety and precision of anticancer therapy.

Microbubbles bound to drug-eluting beads enable ultrasound imaging and enhanced delivery of therapeutics.

Transarterial chemoembolization (TACE) is an image-guided minimally invasive treatment for liver cancer which involves delivery of chemotherapy and embolic material into tumor-supplying arteries to block blood flow to a liver tumor and to deliver chemotherapy directly to the tumor. However, the released drug diffuses only less than a millimeter away from the beads. To enhance the efficacy of TACE, the development of microbubbles electrostatically bound to the surface of drug-eluting beads loaded with different amounts of doxorubicin (0-37.5 mg of Dox/mL of beads) is reported. Up to 400 microbubbles were bound to Dox-loaded beads (70-150 microns). This facilitated ultrasound imaging of the beads and increased the release rate of Dox upon exposure to high intensity focused ultrasound (HIFU). Furthermore, ultrasound exposure (1 MPa peak negative pressure) increased the distance at which Dox could be detected from beads embedded in a tissue-mimicking phantom, compared with a no ultrasound control.

Ultrasound and x-ray imageable poloxamer-based hydrogel for loco-regional therapy delivery in the liver.

Intratumoral injections have the potential for enhanced cancer treatment efficacy while reducing costs and systemic exposure. However, intratumoral drug injections can result in substantial off-target leakage and are invisible under standard imaging modalities like ultrasound (US) and x-ray. A thermosensitive poloxamer-based gel for drug delivery was developed that is visible using x-ray imaging (computed tomography (CT), cone beam CT, fluoroscopy), as well as using US by means of integrating perfluorobutane-filled microbubbles (MBs). MBs content was optimized using tissue mimicking phantoms and ex vivo bovine livers. Gel formulations less than 1% MBs provided gel depositions that were clearly identifiable on US and distinguishable from tissue background and with minimal acoustic artifacts. The cross-sectional areas of gel depositions obtained with US and CT imaging were similar in studies using ex vivo bovine liver and postmortem in situ swine liver. The gel formulation enhanced multimodal image-guided navigation, enabling fusion of ultrasound and x-ray/CT imaging, which may enhance targeting, definition of spatial delivery, and overlap of tumor and gel. Although speculative, such a paradigm for intratumoral drug delivery might streamline clinical workflows, reduce radiation exposure by reliance on US, and boost the precision and accuracy of drug delivery targeting during procedures. Imageable gels may also provide enhanced temporal and spatial control of intratumoral conformal drug delivery.

Ultrasound and x-ray imageable poloxamer-based hydrogel for loco-regional therapy delivery in the liver.

Intratumoral injections have the potential for enhanced cancer treatment efficacy while reducing costs and systemic exposure. However, intratumoral drug injections can result in substantial off-target leakage and are invisible under standard imaging modalities like ultrasound (US) and x-ray. A thermosensitive poloxamer-based gel for drug delivery was developed that is visible using x-ray imaging (computed tomography (CT), cone beam CT, fluoroscopy), as well as using US by means of integrating perfluorobutane-filled microbubbles (MBs). MBs content was optimized using tissue mimicking phantoms and ex vivo bovine livers. Gel formulations less than 1% MBs provided gel depositions that were clearly identifiable on US and distinguishable from tissue background and with minimal acoustic artifacts. The cross-sectional areas of gel depositions obtained with US and CT imaging were similar in studies using ex vivo bovine liver and postmortem in situ swine liver. The gel formulation enhanced multimodal image-guided navigation, enabling fusion of ultrasound and x-ray/CT imaging, which may enhance targeting, definition of spatial delivery, and overlap of tumor and gel. Although speculative, such a paradigm for intratumoral drug delivery might streamline clinical workflows, reduce radiation exposure by reliance on US, and boost the precision and accuracy of drug delivery targeting during procedures. Imageable gels may also provide enhanced temporal and spatial control of intratumoral conformal drug delivery.

Angiosarcoma: hiding in plain sight.

Angiosarcoma is a rare, aggressive soft-tissue sarcoma of endothelial origin that necessitates early recognition, diagnosis, and treatment. The most commonly reported presentation consists of violaceous patches and plaques on the head and neck of elderly white men, with fewer reports affecting patients with Skin of Color. Most cases of angiosarcoma are idiopathic and tend to recur locally with early metastasis, conferring a poor prognosis. We report a case of an 83-year-old Fitzpatrick skin type IV man who presented with a large violaceous-to-black mamillated plaque on the frontotemporal scalp that was clinically highly suggestive of cutaneous angiosarcoma. However, unrevealing histopathology complicated our diagnostic process and delayed management. Immunohistochemistry was invaluable in determining the diagnosis of angiosarcoma. Our case highlights the aggressive nature of cutaneous angiosarcoma, necessitating close clinicopathologic correlation to confirm the diagnosis and initiate treatment.

X-ray imageable, drug-loaded hydrogel that forms at body temperature for image-guided, needle-based locoregional drug delivery.

Liver cancer ranks as the fifth leading cause of cancer-related death globally. Direct intratumoral injections of anti-cancer therapeutics may improve therapeutic efficacy and mitigate adverse effects compared to intravenous injections. Some challenges of intratumoral injections are that the liquid drug formulation may not remain localized and have unpredictable volumetric distribution. Thus, drug delivery varies widely, highly-dependent upon technique. An X-ray imageable poloxamer 407 (POL)-based drug delivery gel was developed and characterized, enabling real-time feedback. Utilizing three needle devices, POL or a control iodinated contrast solution were injected into an ex vivo bovine liver. The 3D distribution was assessed with cone beam computed tomography (CBCT). The 3D distribution of POL gels demonstrated localized spherical morphologies regardless of the injection rate. In addition, the gel 3D conformal distribution could be intentionally altered, depending on the injection technique. When doxorubicin (DOX) was loaded into the POL and injected, DOX distribution on optical imaging matched iodine distribution on CBCT suggesting spatial alignment of DOX and iodine localization in tissue. The controllability and localized deposition of this formulation may ultimately reduce the dependence on operator technique, reduce systemic side effects, and facilitate reproducibility across treatments, through more predictable standardized delivery.

X-ray imageable, drug-loaded hydrogel that forms at body temperature for image-guided, needle- based locoregional drug delivery.

Liver cancer ranks as the fifth leading cause of cancer-related death globally. Direct intratumoral injections of anti-cancer therapeutics may improve therapeutic efficacy and mitigate adverse effects compared to intravenous injections. Some challenges of intratumoral injections are that the liquid drug formulation may not remain localized and have unpredictable volumetric distribution. Thus, drug delivery varies widely, highly-dependent upon technique. An x-ray imageable poloxamer 407 (POL)-based drug delivery gel was developed and characterized, enabling real-time feedback. Utilizing three needle devices, POL or a control iodinated contrast solution were injected into an ex vivo bovine liver. The 3D distribution was assessed with cone beam computed tomography (CBCT). The 3D distribution of POL gels demonstrated localized spherical morphologies regardless of the injection rate. In addition, the gel 3D conformal distribution could be intentionally altered, depending on the injection technique. When doxorubicin (DOX) was loaded into the POL and injected, DOX distribution on optical imaging matched iodine distribution on CBCT suggesting spatial alignment of DOX and iodine localization in tissue. The controllability and localized deposition of this formulation may ultimately reduce the dependence on operator technique, reduce systemic side effects, and facilitate reproducibility across treatments, through more predictable standardized delivery.

Anatomic Subtype Differences in Extramammary Paget Disease: A Meta-Analysis.

Importance: Extramammary Paget disease (EMPD) is a rare, highly recurrent cutaneous malignant neoplasm of unclear origin. EMPD arises most commonly on the vulvar and penoscrotal skin. It is not presently known how anatomic subtype of EMPD affects disease presentation and management. Objective: To compare demographic and tumor characteristics and treatment approaches for different EMPD subtypes. Recommendations for diagnosis and treatment are presented. Data Sources: MEDLINE, Embase, Web of Science Core Collection, and Cochrane Reviews CENTRAL from December 1, 1990, to October 24, 2022. Study Selection: Articles were excluded if they were not in English, reported fewer than 3 patients, did not specify information by anatomic subtype, or contained no case-level data. Metastatic cases on presentation were also excluded. Data Extraction and Synthesis: Abstracts of 1295 eligible articles were independently reviewed by 5 coauthors, and 135 articles retained. Reporting was in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. The analysis was cunducted in August 2019 and updated in November 2022. Findings: Most vulvar EMPD cases were asymptomatic, and diagnosis was relatively delayed (mean, 25.1 months). Although most vulvar EMPD cases were intraepidermal (1247/1773 [70.3%]), radical surgeries were still performed in almost one-third of cases. Despite this aggressive surgical approach, 481 of 1423 (34%) recurred, commonly confined to the skin and mucosa (177/198 [89.4%]). By contrast, 152 of 1101 penoscrotal EMPD cases (14%) recurred, but more than one-third of these recurrences were regional or associated with distant metastases (54 of 152 [35.5%]). Perianal EMPD cases recurred in one-third of cases (74/218 [33.9%]), with one-third of these recurrences being regional or associated with distant metastasis (20 of 74 [27.0%]). Perianal EMPD also had the highest rate of invasive disease (50% of cases). Conclusions and Relevance: The diagnosis and treatment of EMPD should differ based on anatomic subtypes. Considerations for updated practice may include less morbid treatments for vulvar EMPD, which is primarily epidermal, and close surveillance for local recurrence in vulvar EMPD and metastatic recurrence in perianal EMPD. Recurrences in penoscrotal subtype were less common, and selective surveillance in this subtype may be considered. Limitations of this study include the lack of replication cohorts and the exclusion of studies that did not stratify outcomes by anatomic subtype.

Immune Effects of Cryoablation in Woodchuck Hepatocellular Carcinoma.

Objectives: Local and systemic immune responses evoked by locoregional therapies such as cryoablation are incompletely understood. The aim of this study was to characterize cryoablation-related immune response and the capacity of immune drugs to augment immunity upon cryoablation for the treatment of hepatocellular carcinoma (HCC) using a woodchuck hepatocellular carcinoma model. Materials and Methods: Twelve woodchucks chronically infected with woodchuck hepatitis virus and with hepatocellular carcinoma underwent imaging with contrast-enhanced CT. Partial cryoablation of tumors in three woodchucks was performed. Fourteen days after cryoablation, liver tissues were harvested and stained with H&E and TUNEL, and immune infiltrates were quantified. Peripheral blood mononuclear cells (PBMC) were collected from ablated and nonablated woodchucks, labeled with carboxyfluorescein succinimidyl ester (CFSE) and cultured with immune-modulating drugs, including a small PD-L1 antagonist molecule (BMS-202) and three TLR7/8 agonists (DSR 6434, GS-9620, gardiquimod). After incubation, cell replication and immune cell populations were analyzed by flow cytometry. Results: Local immune response in tumors was characterized by an increased number of CD3+ T lymphocytes and natural killer cells in the cryolesion margin compared to other tumor regions. T regulatory cells were found in higher numbers in distant tumors within the liver compared to untreated or control tumors. Cryoablation also augmented the systemic immune response as demonstrated by higher numbers of PBMC responses upon immune drug stimulation in the cryoablation group. Conclusions: Partial cryoablation augmented immune effects in both treated and remote untreated tumor microenvironments, as well as systemically, in woodchucks with HCC. Characterization of these mechanisms may enhance development of novel drug-device combinations for treatment of HCC.

In vitro characterization of immune modulating drug-eluting immunobeads towards transarterial embolization in cancer.

Hepatocellular carcinoma (HCC) is an aggressive liver cancer with limited effective treatment options. In this study, we selected TLR agonists imiquimod (IMQ), gardiquimod (GARD), GS-9620 and DSR 6434, and a small molecule checkpoint inhibitor, BMS-202, for characterization of drug loading and release from radiopaque embolic beads (DC Bead LUMI) for potential use in image-guided transarterial embolization (TACE) of HCC. The maximum drug loading capacity and amount of drug released over time were determined by high performance liquid chromatography and compared with the commonly used anthracycline, doxorubicin hydrochloride (Dox). Maximum drug loading was 204.54 ± 3.87, 65.28 ± 3.09, 65.95 ± 6.96, 65.97 ± 1.54, and 148.05 ± 2.24 mg of drug per milliliter of DC Bead LUMI for Dox, GARD, DSR 6434, IMQ, and BMS-202, respectively. Fast loading and subsequent rapid release in saline were observed for IMQ, GARD, and DSR 6434. These drugs could also be partially removed from the beads by repeated washing with de-ionized water suggesting weak interaction with the beads. Aggregation of IMQ was observed in water and saline. GS-9620 partially decomposed in the solubilizing solution, so loading and release were not characterized. Compared to TLR agonists, slower loading and release were observed for Dox and BMS-202. Potential factors influencing drug loading into and release from DC Bead LUMI including steric hinderance, hydrophobicity, drug pKa, and the electrostatic nature of the beads are discussed. The maximum loading capacity of BMS-202 and Dox in DC Bead LUMI exceeded the maximum theoretical loading capacity of the beads expected from ionic interaction alone suggesting additional drug-bead or drug-drug interactions may play a role. Slightly more release was observed for BMS-202 at early time points followed by a slower release compared to Dox. Further study of these drug-bead combinations is warranted in search of new tools for locoregional delivery of immune-modulating agents for treatment of HCC via drug-eluting bead chemoembolization.

Comparative analysis of the immune response to RFA and cryoablation in a colon cancer mouse model.

The immune response to radiofrequency ablation (RFA) and cryoablation (CRA) was characterized and compared in a colon cancer mouse model. All studies were conducted under a research protocol approved by the National Institutes of Health, Clinical Center, Animal Care and Use Committee. BALB/cJ mice were inoculated with CT26 cells, and randomized to RFA, CRA, or sham treatment. Mice were sacrificed 3 days post-treatment, and tumor, spleen, and serum were harvested. Cell death was determined by Caspase-3 immunohistochemical and TUNEL stains. Immune response was analyzed using flow cytometry, serum cytokine assay and immunohistochemistry. Cell death, necrosis, and apoptosis induced by ablation were comparable in RFA and CRA. Decreased frequency of systemic T-regulatory cells was found in the CRA group. Both RFA and CRA reduced frequencies of several myeloid-derived suppressor cell (MDSC) subpopulations. RFA induced pro-inflammatory cytokine secretion including TNF-α and IL-12 as well as anti-inflammatory cytokines IL-5, and IL-10. CRA augmented secretion of a wider array of cytokines compared to RFA with both pro- and anti-inflammatory properties including IL-1ß, IL-5, IL-6, IL-10, and KC GRO. In the tumor microenvironment, RFA reduced the number of T-regulatory cells, a finding not observed with CRA. Reduction of immune suppression via decreases in T-regulatory cells and MDSC was found to be induced by RFA or CRA. CRA augmented a wider range of cytokines than RFA, which were mainly pro-inflammatory, but also anti-inflammatory. In the tumor microenvironment, RFA demonstrated more pronounced anti-tumoral immunity. Further delineation of specific immunomodulation induced by ablation could inform drug-device development and may play a role in future hypothesis-driven immunomodulatory paradigms that combine immunotherapy drugs with tumor destruction for the treatment of metastatic colon cancer.

Determination of oxygen relaxivity in oxygen nanobubbles at 3 and 7 Tesla.

OBJECTIVE: Oxygen-loaded nanobubbles have shown potential for reducing tumour hypoxia and improving treatment outcomes, however, it remains difficult to noninvasively measure the changes in partial pressure of oxygen (PO2) in vivo. The linear relationship between PO2 and longitudinal relaxation rate (R1) has been used to noninvasively infer PO2 in vitreous and cerebrospinal fluid, and therefore, this experiment aimed to investigate whether R1 is a suitable measurement to study oxygen delivery from such oxygen carriers. METHODS: T1 mapping was used to measure R1 in phantoms containing nanobubbles with varied PO2 to measure the relaxivity of oxygen (r1Ox) in the phantoms at 7 and 3 T. These measurements were used to estimate the limit of detection (LOD) in two experimental settings: preclinical 7 T and clinical 3 T MRI. RESULTS: The r1Ox in the nanobubble solution was 0.00057 and 0.000235 s-1/mmHg, corresponding to a LOD of 111 and 103 mmHg with 95% confidence at 7 and 3 T, respectively. CONCLUSION: This suggests that T1 mapping could provide a noninvasive method of measuring a > 100 mmHg oxygen delivery from therapeutic nanobubbles.